Have you heard any one talk as though they're swallowing, or choking, on certain words?

The first time I heard it I thought he had some sort of speech impediment, or throat spasm or something. He said words like, “school,” as though he’s choking on the “chool” part. I thought it was just him, and he had a problem, but the other day I heard another narrator doing it too, just not nearly as bad. They both had British accents.
Is it just a habit some people get into, or is it a physical problem?